Combined ahead and astern turbine.



H. W. RIDSDALEcz COOK. COMBINED AHED AND ASTBRN TURBINE.

APPLIOATION FILED PEB.1L, 1911.

` Patented Nov. 28, 1911.

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Hanauer Wnnarnnr ernennen, or tonnen, ann tirantes* entre' court, or

iii/antenna :amenait-rn, assrenons 'ro errantes aannemen Paasmars, or

NEWCASTLE-UPON-TYNE, ENGLAND.

COMBJNJEID MHRA@ AMCD ASTEltll' TURBINEI.

incense To all whom t may concern Be it known that we, HERBERT VVHEATLEY RmsDALE, a subject of theV King oi Great Britain and Ireland, and residing at Capel House, 62 New Broad street, London, E. C., England, and 'STANLEY SMITH Coon', a subject of the King of Great Britain and reland, and residing at Turbinia llVorks, Vitalis-V end-onflyne, in the county of Northumber land, England, have invented certain new and useful Improyements in and Relating to ombined Ahead and Astern rlurbines, of which the following Vis a specification.

rlllhis invention relates to improvements in the combination of an ahead and an astern turbine, each of Which'may torni an entire or a portion only ot the ahead and astern turbine systems. In such constructions of combined ahead and astern turbines as have hitherto been proposed, it has been usual to provide separate balancing pistons for the ahead and the astern turbines, the steam leaking past such balancing pistons being carried to the common exhaust o'l the two turbines either through the interior of the rotors or by special pipes provided forl that purpose.

The object ot the present invention is to provide an improved and simplified arrangement for e'lecting the balancing of such combined ahead and astern turbine.

The invention consists in an arrangement of combined ahead and asternturbines in Which Huid from a stage of one of the turbines is admitted to the interior of a hollow rotor common to both turbines, While a packing separates the rotor interior from the other turbine and thereby enables the required balancing thrust to be obtained with either turbine in operation.

The invention also consist-s in the improved balancing arrangement of combined ahead and astern turbines as hereinafter described.

Referring now to the accompanying drawing Which illustrates one method of carry ing the present invention into effect, there is shown in section a combined ahead and' astern turbine in which the ahead turbine Specification of Letters Patent.

.application lecl February ifi, 19M.

Patented ltlovn 2id, limita serial no. Scatta part comprises an impulse Wheel, c, followed by a reaction stage, a, While the astern turbine comprises an impulse Wheel, f, 'followed by a reaction stage, The rotor, e, oit the astern turbine reaction stage is supported on an extension of the rotorycl, While the impulse Wheels `c and f are suitably attached at opposite ends oit the rotor, d, which .is f

common to both the ahead and astern turbine par'ts. 'llhe reaction stages of both. the ahead and astern turbine parte being thus adjacent are arranged to exhaust into a common eduction pipe, g, and thus it will be seen that the inactive turbine part always rotates idly in the low pressure steam enn hausted from the turbine part in action.

lin the arrangement ot the combined ahead and astern turbines according to the present invention, the axial thrust produced when the turbine drives a propeller in either direction is balanced by the steam pressure on a balancing piston Which is subjected to the [luid pressure in one of the turbine parts only. Such a piston as shown at, c, is conveniently placed'at the ahead turbine end otz the rotor, Which, for the purpose oft enabling the piston to be subjected to the pres sure of the fluid in a stage of the astern turbine.,x is hollow and open at both ends. rllhe fluid thus passing fromv the chamber containing the impulse Wheel, f, through holes enters the rotor interior and thence passes by axial passages, z', into thechamber containing the piston, 7c. By providing a packing m between the balancing piston, 7c, and the turbine casing7 no vhigh pressure wWorking tluid (With the exception of that which may leak through the packing m), can pass from the ahead turbine directly into the chamber conta1n1ng the balancing" piston, lt will thus be seen that when the ahead turbine is in action, the rotor interior is filled with low pressure steam, but is filled With higher pressure steam when the astern turbine is in action,

lt is sometimes desirable to form the ahead turbine part ot the rotor in two parts, Z and it, which are of ditlerent diameters and thus provide an annular surface, g, at

\ the pistonc, is sufcient to produce the rethe place where the two parts meet. As such an annular surface is subjected to a ditierence of pressure, it can be used as a balancing surface when the ahead turbine is in action. ln all cases however, it will be seen that the diameter of the balancing piston, Je, is determined by-arranging-that the annular area between it and the mean diameter of the ahead turbine will give with the prevailing pressure the thrust required to balance or the requisite amount in Aexcess of or in defect of the thrust of the propeller when being driven ahead.

During ahead running the working fluid such as steam is admitted to the ahead turbine by means of nozzles, a, from which it passes through the blading of the impulse wheel, o, and is further expanded in the subsequent reaction stages. The exhaust steam then passes through the reaction blading of the astern turbine, b, and enters the" rotor interior by means of the holes, y', thereby producing a dierence of pressure on the opposite sides of the balancing surface, g, which, together with the thrust produced on quired balancing thrust. Similarly when the astern turbine is in action, steam is admitted thereto'by nozzles, p, and after having-passed through the blading of the impulse wheel, f, isfurther expanded in a subsequent reaction stage, ti e rotor interior being now hlled with steam at the pressure of that in the chamber containing the impulse wheel, f.

In order to obtain the required 'balancing thrust, the mean diameter of the astern reaction blading-and the balancing piston, 7c, are chosen so that the annular area between the diameter of the balancing piston, and the mean diameter of the reaction blading, b, will give with the prevailing steam pressure, the required balancing thrustln some cases a step or annular surface is formed in the astern reaction stage in amanner similar to that shown in the reaction stage of the ahead turbine.

lt will be seen that the steam leaking past the labyrinth packing, m, between the balancing piston, 7c, and turbine casing, whichever turbine is in operation, passes' through the blading of the other turbine? but as the amount of such leakage steam is usually small, no appreciable resistance to vrotation will be produced thereby. lf desired, however, suitable valves may be provided to connect the admission space of the ahead or astern turbine to the exhaust pipe, which valves may be designed to close when the pressure in this admissionl space has risen to a given amount, or they may be designed to be so coun with the ahead and astern admission as to be actuated A .ieously the sans; means, or

they may be separately hand perated. By e this means leakage steam from'either turbine can flow directly to the exhaust space without passing through the blading of the other turbine.

As -is usual in such turbines, suitable 7 means are provided in order to maintain a `constant clearance between the packings, 7',

at the place where the rotor shaft passes through the turbine casinff. Such means may consist, as shown, in forming within the rotor shaft, s, a chamber, t, to which steam is admitted by radial passages, u, in the rotor supporting the framework, and in communication with the chamber containing the impulse wheel, c. s lInstead of arranging the single dummy or balancing piston at the admission end of the ahead turbine, it can be placed at the corresponding end of the astern turbine. With this arrangement the interior of the s rotor, when the ahead turbine is in operation will be lled with steam at a pressure corresponding to the pressure of the steam admitted to the ahead reaction blading. The pressure on the gland packings where 9 the rotor shaft passes through the casingA will correspond to that obtaining in the interior of the rotoil and therefore that in the admission s ace of either the ahead or astern reaction lading. rll`he hollow rotor 9 may however if preferred be closed by a transverse partition at any point or be closed at both ends. ln the latter case the spaces between the ends of the rotor and the turbine casing'are placed in open communi- 1 -cation with one another by means of a pressure equalizino pipe or pipes external to the turbine casing, or by means of one or more passages formed in the casing itself.

This invention is also particularly api plieable tothe ease in which either the ahead or the astern 'turbine'or both are low pressure turbines of the reaction. type; also, it is preferable that the single dummy or balancing piston should be placed at the ahead l" or astern end of the rotorA according 'to whether the ahead or astern turbine is adapted to work with the high pressure admission steam. By this means the pressure dii'eience'on the before mentioned gland l packings is reduced to a minimum. The invention can however'be also applied to cases in which high pressure admission steam is used for either or both the ahead and astern turbines, the gland packings being suital'ilj,T l designed to withstand the high internal pressures. The invention is also particularlj.' applicable to cases as shown in which one or other of the turbines Aor both are ofA the mixed type, via., consisting in one or l' tur,

constructions by 'which the invention can be carried into eit'eet are capable ot very considerable modifications Without in any Way departingnroni the spirit ot the saine.

Haring non described our invention what We claim ae nerr and desire to secure bv l. t tluid onerated turbine having in coinbinatio-n an ahead and an astern turbine part, a hollow rotor coininon to said parte, ivorltinggg tluid troin a re ol' one oli' the st turbine parte being adinitted to the interior ot said rotor7 packing ineans separating the with either turbine part in operati-on.

3. il. lluid operated turbine having in co1nbination an ahead and an astern. turbine part.I a hollow rotor open at both ends and common to both turbine parte7 Working' ,tluid troni avstage oi one et the turbine parte being;l admitted to the interior of .said rotor through one end thereof, packing' ineens near the other end olf said rotor, said ineans ser arating the rotor interior from the other turbine part? whereby the required balancing' thrust is obtained with either turbine part in operation.

4e. t fluid o} 'ierated turbine having; in coinbination an ahead and an astcrn turbine part, a hollow rotor open at both ends and common to both turbine nare Working fluid from a etage oit one ol. the turbine parte being admit-ted to 'the interior of the rotor thrcalgh one end thereot7 a balancing piston att-ached to the other e* d ot rotor and subjected to the tluid i eure in. said inte rior, packing' ineans f minding Said piston and separating the ot ,r turbii e'tronr the rotor interior a'fl'iercliiy the required balancu ing` thrust is obtained with either turbine partln operation.

il. 'duid operated turbine having in combination an ahead and an astern turbine part, a hollow rotor common to .siiid parts1 means for admitting Working .fluid from a etage of the aetern turbine 'part into the interior of said rotor, 'packing1 means separat-- said interior trein the ahead turbine bart whereby 'the required balancing,v thrust is obtained With either turbine part in action.

Y 6. A tluid operated turbine having' in combination an ahead and an astern 'turbine part, a hollow rotor common to said parte, iuid ,troni a Stage ot the astern turbine part being admitted to the interior ot said rotor, a balancing piston attached to said rotor at the ahead turbine l end thereof, packing means .surrounding` said pieton and separating the rotor interior from the ahead.

turbine part, the dimensione ot Said piston being determined witl'i'r Spect to the mean diameter of the ahead and astern turbine parte respectively;7 to give with the prevail ing steain prcsaura-i tbe requiredbalancing thrust With either turbine part in action` .arating the rotor interior from thcV other turbine part, wlierebi-Y 'the required balancing thrust is obtained with either turbine part in liction.

8. l tluid operated turbine having' in combination an ahead and an astern turbine part, an impulse stage followed by a` reaction stage in cat-h oli said parts, a hollourv 'rotor common to said parts and open at both ends, workinnl'tluid lrorn the iinpulSe stage ot the astern turbine being;1 admitted to the interior ont the rotor tl'irougli oney end thereof, a balancing pieton attaeiied to the rotor at tliehead turbine end, packing ine-ans eurrounding; said piston and separating the rotor interior troni the ahead turbine paru u'herebjv the required balancing' thrust is obtained. with either turbine part in action. 9. ift l'luid ojivierated turbine having; in

combination an ahead and an astcrnturbine part within a coinnion easing', a hollow roter connnon to both of said parte, means for ad initting fluid t'roin a stage ot the astern turbine partto the rotor interior, a balancing piston placed at 'the ahead turbine end of said rotor and subjected to the tluid pressure in the astern turbine part, a. packing between said piston and the turbine casing, V

an annular balancingl surface termed on the rotor oit one or both oit the turbine parte, the dimensions of the balancing; piston being chosen with regard to the inean diameter of both turbine parte to give With the prevailing tluid pressure the required balancing thrust with either turbine part in action.

10. A tluid operated turbine having' in con'ibination an ahead and an aetern turbine part within the saine casing, a. hollow rotor common to both ot said parte and open at both ends, workiiu; fluid 'trema Stage of the astern turbine part being' admitted to the rotor through one end thereof, abalancing" piston carried by said rotor at the ahead turbine end thereof and subjected to the pressure in the rotor inerior, a packing be tween said piston and the turbine easing an annuler balancing surface formed on the ahead turbine part of the common rotor whereby the dimensions of the balancing piston can be chosen with respect to the mean diameter of the ahead turbine part and of the asern JLurbine part to give with ehe prevailing Huid pressure Jeine required baancing thrust with either turbine' part in eet-ion.

in tes'imony whereof We have Signed our names to this specification in the presence of two subscribing Witnesses.

HERBERT WHEAQLEY EIDSDALE. STANLEY SMITH COOK.

Witnesses te `'die signature of Herbert v Wheatley Ridsdae:

' A, E. TAYLOR,

P. A.^0U'ITWA1TE; "1V itnesses to *she signature o Sanley Smith Cook:

FREDERIQK GORDON HAY BEDFORD, ALBERT WILLMM Peek@ 

